[PATCH 4/6] clk: Fix rate caching in clk_get_parent_rate()

[Samuel Holland]

On 2/20/23 10:11, Sean Anderson wrote:
> On 2/20/23 00:59, Samuel Holland wrote:
>> clk_get_rate() can return an error value. Recompute the rate if the
>> cached value is an error value.
>>
>> Fixes: 4aa78300a025 ("dm: clk: Define clk_get_parent_rate() for clk
>> operations")
>> Signed-off-by: Samuel Holland <samuel at sholland.org>
>> ---
>>
>>   drivers/clk/clk-uclass.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
>> index 5bce976b060..9d052e5a814 100644
>> --- a/drivers/clk/clk-uclass.c
>> +++ b/drivers/clk/clk-uclass.c
>> @@ -520,7 +520,8 @@ ulong clk_get_parent_rate(struct clk *clk)
>>           return -ENOSYS;
>>         /* Read the 'rate' if not already set or if proper flag set*/
>> -    if (!pclk->rate || pclk->flags & CLK_GET_RATE_NOCACHE)
>> +    if (!pclk->rate || IS_ERR_VALUE(pclk->rate) ||
>> +        pclk->flags & CLK_GET_RATE_NOCACHE)
>>           pclk->rate = clk_get_rate(pclk);
>>         return pclk->rate;
> 
> The correct fix here is
> 
>     /* Read the 'rate' if not already set or if proper flag set*/
>     if (!pclk->rate || pclk->flags & CLK_GET_RATE_NOCACHE) {
>         rate = clk_get_rate(pclk);
>         if (!IS_ERR_VALUE(rate))
>             pclk->rate = rate;
>     }
> 
>     return rate;
> 
> No point caching errors.

Good point. I will do this for v2.

Regards,
Samuel